The invention relates to a blood pump.
A blood pump which has been described in the patent literature comprises substantially a squeeze pump containing valves and operated by a pumping medium in the form of a pulsating fluid which separates a flexible pumping tube from a rigid outer wall, an atrium on the entry side and a tube bend on the exit side. The component parts of this pump which come into contact with blood are intended to be "compatible" with blood and it is proposed that they should consist of a specific material, namely "Dacron velour". However, this precaution is not yet sufficient since a negative surface charge of about 100 mV is also required. The prior proposal fails to provide for this need. At the Congress of the American Society for Artificial Internal Organs held in April 1973, Sawyer drew attention to this requirement. Another major objection to the above mentioned pump is the damage done to the blood by conditions of flow which are not physiological. The blood is highly stressed for shear and vacuum pressure in association with "stagnant pockets" destroy the red corpuscles (mechanical hemolysis). The proteins in the blood are denatured.